updates/corrections required in acefc

[dlopezaldama]

Updates/corrections required in acefc:

1. Prevent losing the penultimate node in the unified energy grid
2. Correct calculation for MF6/LAW5/LTP=2 (residual cross-section expansion)
   Implement linearization of elastic scattering for MF5/LTP>2 (nuclear + interference)
   Correct treatment of identical particles for MF6/LAW5/LTP>2
3. Correct/enhance treatment of MF6/LAW7
4. Enhance the acelf6 subroutine:
   Improve secondary energy grid calculation for MF6/LAW=6
   Safer smoothing option for MF6/LAW=1/LANG=2 at low energies (avoid grid misordering)
   Fix conversion from LAW=1 to LAW=7 when NEWFOR=0
   Prevent potential division-by-zero errors
5. Protect the construction of the union list of discrete photons and prevent division-by-zero errors
6. Add code against invalid pointer assignment and division-by-zero
7. Update acelcp:
   Improve heating calculation (correct CM to Lab conversion)
   Correct probability validity for energy laws in ACE files (laws 33, 66, 67)
   Improve the treatment of allowed interpolation laws and their use in integrations
8. Correct LAW44 treatment in the subroutine change
9. Fix acefix to take mass ratios for p, d, t, He3, and alphas from the phys module
10. Update consis: add checks for law67 and adjust consistency tests
11. Enhance law67 plotting + corrections to aplodd, aploxp, getl7
12. Store thresholds with 9-digit precision for consistency
13. Increase array size, use big=1.0e10 consistently, and clarify photon-production output
    for incident charged particles